WATERTOWN, Mass.—Authorities Friday arrested a 19-year-old college student suspected in the deadly Boston Marathon bombings, following a manhunt that for a full day had paralyzed a metropolis.

A developing timeline of the Boston Marathon bombing and subsequent suspect manhunt.

Police and Federal Bureau of Investigation agents converged on a house here around 7 p.m., officials said. Before taking him into custody nearly two hours later, authorities exchanged gunfire with Dzhokhar Tsarnaev, who was found hiding in a boat, covered in blood, by a resident checking on his backyard.

Col. Timothy Alben of the Massachusetts State Police announces authorities have captured Dzhokhar Tsarnaev, the 19-year-old suspect in the Boston Marathon bombings, at a house in Watertown, Mass.

Police said Mr. Tsarnaev had been wounded in an early-morning firefight with police. They said it was unclear if he suffered additional injuries in the shootout at the boat.

"CAPTURED!!! The hunt is over," tweeted the Boston Police Department. "The search is done. The terror is over."

Essay

Mr. Tsarnaev is one of two brothers alleged to have exploded two homemade bombs at the marathon Monday, killing three people and injuring more than 175. He was taken to a hospital and listed in serious condition.

Neighborhood residents cheered police after the arrest. An officer said, "God Bless America" over a megaphone as police vehicles ferried away Mr. Tsarnaev. "We've closed an important chapter in this tragedy," said President Barack Obama, after the capture was announced.

The arrest capped a violent overnight spree that began with the fatal shooting of a campus police officer at the Massachusetts Institute of Technology and included a police chase through Boston suburbs. The brothers, carrying an arsenal of explosives, fled police before dawn Friday in a stolen Mercedes and hurled pipe bombs in a firefight with police, which left one officer injured.

ENLARGE

The older brother, 26-year-old Tamerlan Tsarnaev, wearing what appeared to be an explosive vest, was shot by police and died shortly after, while the younger brother narrowly escaped—after first running over Tamerlan's body with the Mercedes, officials said.

Authorities gave no indication of what motivated the brothers. Their family roots stretch to the Russian republic of Chechnya, which has been a wellspring of terrorism over the years.

Map: Boston Area

The FBI in 2011 had interviewed the older brother, Tamerlan, at the request of the Russian government but found nothing suspicious, a U.S. official said Friday.

Friends said the two brothers, especially Dzhokhar, had settled comfortably into U.S. society. He was enrolled at the University of Massachusetts Dartmouth.

The brothers, who lived in Cambridge, Mass., had escaped notice for three days after Monday's bombings. Late Thursday, the FBI released pictures and videos taken from security cameras near the marathon's finish line.

Broad release of the images apparently triggered a chaotic getaway attempt by the brothers, who arrived separately in the U.S., one around 2002 and the other in 2003 or 2004.

"Releasing that video really expedited things. People actually did recognize them," said Rep. Michael McCaul (R., Texas), chairman of the House Homeland Security Committee. "That moved things along more quickly, to the point they decided they had to get out of town."

Political fights largely were sidelined during the hunt for the bombers. But on Friday evening, Sen. Lindsey Graham (R., S.C.), via his Twitter account, suggested the White House consider holding the suspect in military custody. President Obama has ordered that U.S. citizens such as the younger Mr. Tsarnaev who are accused of terror offenses should face trial in civilian courts.

After Monday's attack, the brothers apparently stayed around the neighborhood where they had settled after immigrating, authorities said.

On Tuesday, Dzhokhar came to an auto-body shop to pick up a Mercedes he had dropped off for repairs, said Gilberto Junior, who works at the shop.

The younger brother was jittery, said Mr. Junior. "He was biting his nails and when he was talking to me his legs were like this," Mr. Junior said, shaking one leg. "He said, 'I need the car now. I need the car right now.' "

At 5:20 p.m. Thursday, the FBI released the photos and video of the brothers. Investigators said the two men apparently decided they needed a car to flee. It wasn't clear why they didn't use the Mercedes from Mr. Junior's shop.

Shortly before 10:20 p.m., MIT police officer Sean Collier, 26 years old, was ambushed and fatally shot in his car. Massachusetts State Police officials at first thought the shooting was unrelated to the marathon bombings.

The Boston Bombings

A look at the events that have happened since two deadly explosions that shook the Boston Marathon on Monday.

Terror in the U.S.

At MIT, police used flashlights and search dogs to search the campus for more than an hour, with officers circling parts of the campus and clearing away passersby. Then the officers ran into their cars and sped away.

After the MIT shooting, the brothers allegedly used a gun to steal a Mercedes sport-utility vehicle, briefly kidnapping the driver and telling him they were responsible for the bombings, U.S. officials said. The victim escaped from his captors at a gas station in Cambridge, Mass. His captors then used his ATM card to withdraw cash.

The driver notified police, who spotted the stolen Mercedes and began the chase, with the suspects throwing explosive devices out of their vehicle.

Authorities believed they had trapped the car in a densely populated residential neighborhood of Watertown. But the brothers put up a fight.

Adonis Karageorgis, a 35-year-old dental student, said he saw the sky light up from his apartment. "You could just smell the smoke," he said. "It went high in the sky."

Tamerlan Tsarnaev got out of the car and was shot, authorities said. Richard Donohue Jr., a police officer, was seriously wounded in the firefight.

Seeing his brother shot, Dzhokhar threw the Mercedes into reverse and drove the car over his brother's body, a U.S. official said. Then he got out, and Massachusetts police said he escaped on foot.

Tamerlan was pronounced dead at a hospital Friday around 1:30 a.m., and the search for the surviving brother intensified. Hundreds of police swarmed the Watertown neighborhood. Helicopters flew overhead.

For most of the day, Boston was virtually shut down as authorities advised residents to stay locked indoors. Public transit, including commuter rail, buses and subways, were halted and Amtrak closed service to and from the city. Schools and offices were closed.

Chalena Graustuck, 23 years old, who lives a few blocks from the brothers' home, said she felt trapped: "It's just scary. I don't feel safe at all. I want to get on a plane and go far away from Cambridge but now we're stuck here."

Friday evening, the search narrowed to the house with the boat in Watertown. Irene Santoro, who lives on the street, said police arrived around 7 p.m. "They started coming down in 10s and 20s and 30s," she said. "It was like something you would see on TV. … My heart was palpitating."

The suspect was captured around 8:40 p.m. "This was truly an absolutely intense investigation,'' said Richard DesLauriers, head of the FBI's Boston office. "As a result of that, justice is being served for the victims of these terrible crimes.''

Authorities said it appeared the brothers were acting alone. The FBI and local police Friday evening briefly took away for questioning three people in their late teens or early 20s at an apartment complex in New Bedford, Mass., not far from where the younger Mr. Tsarnaev was attending college.

Witnesses said an FBI agent at the scene made comments suggesting authorities were interested in gathering information about the suspects.

Corrections & Amplifications The alleged carjacking victim of the accused Boston Marathon bombers escaped from his captors at a gas station in Cambridge, Mass. His captors then used his ATM card to withdraw cash. A previous version of this article incorrectly reported that the victim was forced to withdraw cash and then was released by his captors. The accompanying maps and chronologies also incorrectly said the victim was released. In addition, the carjacking occurred on Brighton Avenue in Boston. The maps incorrectly indicated it occurred in the area around Third Street in Cambridge. The erroneous information originated in a Cambridge Police Department news release issued on April 19 and in law-enforcement briefings.

This copy is for your personal, non-commercial use only. Distribution and use of this material are governed by our Subscriber Agreement and by copyright law. For non-personal use or to order multiple copies, please contact Dow Jones Reprints at 1-800-843-0008 or visit www.djreprints.com.